Hi M.,
I have two children an I didn't experience cradle cap with them, but they do both suffer from extreme eczema (I don't know if I spelled that right). What works best for them is a cream that has no fragrance at all in it. I know I am very tempted to try to smelly lotions, but that is where the problem only gets worse as the fragrance drys out the skin even more for people with sensitive skin. Look at the label because it may say scent free on the front, but if fragrance is listed as an ingredient you should stay clear of them. I recommend Eucerin or Aquaphor. Aquaphor is really expensive and there is no alternative that I have found, it is also mostly petrolium jelly and therefore greasy, so I would try the Eucerin first. If you go to walmart, they carry an alternative to the Eucerin that is much more affordable. You should look for the thick, paste-type cream, not the lotion.
A good way to keep moisture in as well is to put a cap on him, that way they skin fully absorbs the moisture and the best time to do this is after a bath. You should apply the cream several times a day until it clears up and then you can cut back to only after baths. I hope this helps. Congratulations on your first child, it truly is a blessing.